Wednesday, September 14, 2011
BIO Week 1- LEC 2
What is Biodiversity?
Variations in species
Variations in adaptation to climate, surroundings (ecology)
Interactions between different streams in biology
Variations in genes
Shaped by billions of years of evolutionary history of life forms interacting
with each other and their environment
Altered by human activity with lasting impacts at large scales that are
difficult to predict.
o Descent with modification from common ancestors
o Wrote “Origin of Species”
What factors contribute to threats to native freshwater mussel biodiversity in the
Great Lakes region?
Invasive species competing for resources
Water temperature change
Two types of mussels:
Dreissenidae & Unionoids
TABLE: answer- C.
Life Cycles and Larval Types:
Freshwater bivalves develop in 3 ways:
Bivalves: developed in two sections-bilateral symmetry
Develop the most in the early stages (larval stages)
1. Producing veliger larvae (eg. Dreissena Polymorpha)
2. By releasing fully developed young mussels (rare)
3. By passing early development as a parasitic stage on a host (eg. Unionids) Wednesday, September 14, 2011
Unionids Life cycle:
Juveniles sit in the mud for months, eating and growing- then become an
adult (sexually mature)
In the Unionids, there is female gonads in females and male gonads in males
Males produce sp